Oil defrosting unit



March 24, 1953 c. WHITE, JR 2,632,304

OIL DEFROSTING UNIT I Filed Aug. 1, 1949 Inventor lrby 6'. While, Jr

By MM 8 Patented Mar. 24, 1953 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to novel and useful improvements in refrigerationapparatus and the operation thereof.

An object of this invention is to improve the operation of conventionalor non-conventional refrigeration apparatus by storing, heating andcirculating a non-aqueous liquid or other liquid which has a strongtendency to remain in the liquid state throughout a large range oftemperature change to accomplish the defrosting of the evaporator in theconventional or non-conventional apparatus.

Another object of this invention is to improve the mode of operation ofrefrigeration apparatus and more specifically the defrost cycle thereofregardless of the type of motivation used for the defrosting medium inthe apparatus by introducing the defrost medium throughout the pertinentparts of the structure including the cooling unit in the liquid stateand retaining it in the liquid state at the initial stages, during themiddle stages and at the final stage of the defrost cycle of operation.

Ancillary objects and features will become apparent in following thedescription of the preferred illustration setting environment of theinvention in the accompanying drawing wherein:

Figure 1 is a partial schematic and partial sectional view showing astructural arrangement of a refrigeration apparatus.

Figure 2 shows part of the electrical system.

The illustrated structure include a number of conventional elements.There is a cooling or evaporator unit generally indicated at H!receiving refrigerant through a feed line l4 having an expansion valve12 operatively connected therewith. The valve i2 is controlled by thefeeler it which has a capillary actuating connection I8 for the valvel2. The feeler bulb I6 is firmly connected with the line 20. A solenoidvalve 22 is interposed in a conduit or line 24 which is connected withthe expansion valve [2 at one end and extends through the heat exchanger26 to connect with a refrigerant receiver or storage reservoir 93 at theother end. The suction line 28 is operatively connected with the heatexchanger and with the closed chamber Or tank 39, the tank 39 beinginsulated from the surrounding atmosphere by the insulation 32therearound, as is known in the art.

A compressor 54 operated by a motor 56 receives refrigerant gas from thechamber 30 through a suction line 62" and delivers compressedrefrigerant through the condenser line 64 including the condenser 61 tothe receiver 98. The condenser line 64 is provided with a manual servicevalve and suction line 82 is provided with a service valve 65.

The container 30 also stores the lubricating oil for the compressor 54and oil flows from the con tainer 30 into the casing of a compressor 54through an oil line 6-0 having a service valve 68. A pressure equalizingline 58 above the oil level in the container 30 admits gas into thecasing of the compressor 54 so that the oil level in the casing of thecompressor 54 will correspond to the oil level in the container 30. Aservice valve 10 is placed in the equalizer line 58.

With the exception of the solenoid valve 22 the above describedrefrigerator system is conventional and forms the basic system withwhich the present invention is combined.

The defrosting operation utilizes a line 34 extending into the cooler34, and having a coil 38 disposed in the drip pan 39 and connectingthrough a check valve 42 and conduit 40 to the supply line H for theevaporator. The check valve 42 allows flow in one direction through line34 and inhibits return flow into the line 34 from the line l4. At theopposite end of the line 34 there is provided a connection with acirculating pump 45 and a manually operatively service valve 48 isconnected in the line 34 upstream of the flow therein during the defrostcycle of operation. A length of tubing or pipe 50 is connected to theinlet side of the circulating pump and the interior of the tank 30, aservice valve 52 being positioned in line 50.

The typical electrical system involved in the illustration includessupply conductors 12 connected to a timer l4 and supplied by a suitablesource of electrical power (unshown), various electrical conductors andother mechanism. Noting first the electrical timer (4, there are twoelectrical conductors 16 extending therefrom and terminating in themotor controller 18. Two other electrical conductors extend from theelectrical line and terminate in the circulating pump 46. Electricalconductors 82 extend from the timer and connect operatively with the fanor blower generally indicated at 86. This fan is disposed behind thecooling unit to serve its conventional function. The final conductor 88extends from the timer and terminate in electrical connection with thesolenoid valve 22.

Suitably connected for operation in the tank 30 is a two-stagethermostat 90 and a first heater element 92 together with a secondheater element 94. A switch I00 connects the supply 12 to conductors I02which in turn are connected to the time 14, a branch circuit I04supplies energy to the heaters 92 and 94 with the thermostat switch 90selectively connecting the heaters across the conductors I04.

The operation of the described structure is typical of a substantiallyconventional refrigeration apparatus. Now, the prior art is replete withstructure arranged in various mannerisms which operate for the purposeof cooling the unit l and then defrosting the same at timed intervals orresponsive to other outside stimuli. It is in the defrost cycle ofoperation that my invention resides. Various patents show differenttypes of defrosting operations during the defrost cycle however, in alldefrost cycles of operation there is the so-called hot gas operation, atypical one being the steps of taking hot gas from the compressorthrough a tank to store heat in an organic solution during the normaloperation of the system which is to be later used in the reversal of thecycle. In the majority of instances there is a, change of statenecessary for the successful operation in the defrost cycle. This changeof state referred to, is the passing of the heating medium from the gasto the liquid state or from the liquid to the gaseous. In contrast,there is herein a system of defrosting refrigerating cooling coils byusing a quantity of a particular class or group of liquids which have astrong tendency to remain in the liquid state throughout a large rangeof temperature change. The liquid may or may not be aqueous and ispreferably nonaqueous. Ordinary refrigeration oil of the same type asemployed in a refrigerating system for lubricating the compressor ispreferable.

The oil is heated by means of the electrical elements 92 and 94 whichare thermostatically controlled (by a thermostat 9D) and mounted in themanner disclosed in the illustration. Preferably, the first heatingsection has the capacity necessary to recover heat losses from the oildue to the insulating casing, oil returning through the cooling coils inthe normal refrigerating cycle and the suction gas passed through theoil storage tank.

The second electrical heater section has the capacity necessary torecover the heat losses in the process of removing frost and ice fromthe cooling coil or coils and of course, the drip pan 39. Thethermostatactuates the electric heater in two stages of operation, from the normaloperating temperature of approximately 160 F., the first heater stagebeing energized when the temperature of the oil is reduced 3 F. and thesecond heater section becomes energized with a further reduction of 10F.

At a predetermined time the electrical timer 14 which is in reality adefrosting controller is rendered operative so that the compressor motorwill stop and the liquid line solenoid 22 will close, the fan 86 will berendered inoperative and the circulating oil pump 46 will be renderedoperative. The pump 46 takes heated oil from the closed chamber 30 andpumps it through the line 34, the coil 38, check valve 42 and conduit 40into the coils of the cooling unit I9. It passes through the check valve42 in this operation and also throughthe suction line 28 after passagethrough the heat exchanger 25 for ultimate disposition in the closedchamber 30. This cycle of operation is the defrost cycle, it being notedthat the oil is ultimately re-deposited in the tank 30 so that it isreheated and continues in the cycle until sufficient heat has beentransferred from the heat source to melt the frost and ice on thecooling coils and drip pan whereby efficiency of the unit is maintainedat the engineering level.

After the coils and drip pan have been defrosted the timer 14 rendersthe circulating pump 46 inoperative, opens the liquid line solenoid 22,makes the fan 86 operative and places the compressor motor under anelectrical load so that the refrigerating system is again in normaloperation.

Having described the claimed as new is:

1. A defrosting refrigerating system including, a refrigerantcompressor, a receiver for condensed refrigerant, a condenser tubeconnected between said compressor and said receiver, an evaporator coil,a refrigerant conduit connected between said receiver and the inletterminal of said evaporator coil, temperature responsive valve means insaid refrigerant conduit for admitting refrigerant from said receiver tothe inlet terminal of said evaporator coil, a return conduit from theoutlet of said evaporating coil to said compressor, a chamber in saidreturn conduit, a quantity of compressor lubricant oil in said chamber,an oil conduit from said chamber to the inlet terminal of saidevaporating coil, a check valve in said oil conduit to prevent reverseflow of refrigerant or oil through said oil conduit to said container, asolenoid valve in said refrigerant conduit, a pump in said oil conduit,electrical control means operative to periodically close said solenoidvalve and render such compressor inoperative, and to render said pumpoperative to pump said oil into said evaporating coil, said 011 passingthrough said evaporating coil and said return conduit to said chamber,thermostatically controlled heating means for maintaining the oil insaid chamber at .a predetermined temperature.

2. A defrosting refrigeration apparatus including a closed refrigeratingsystem including a compressor, a refrigerating coil, connections betweensaid compressor and said coil, said connections including a condensertube, a receiver and an expansion valve, suction line means, connectingsaid refrigerator coil with said compressor, a chamber in said suctionline, said chamber providing oil storage space, said compressor pumpingrefrigerant to said refrigerating coil, a separate conduit from saidchamber to said refrigerating coil, a pump in said separate conduit, acheck valve in said separate conduit, a solenoid valve in series withsaid expansion valve, a time invention, what is responsive controller toperiodically close said solenoid valve, deenergize said compressor andstart said pump to circulate oil from said chamber through saidrefrigeration coil, means for heating the oil in said chamber.

IRBY C. WHITE, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,819,510 Hebeler Aug. 18, 19312,228,364 Phillip Jan. 14, 1941 2,243,466 Kucher May 27, 1941 2,301,656Hirche Nov. 10, 1942 2,451,682 Lund Oct. 19, 1948 2,452,102 CocanourOct. 26, 1948' 2,459,173 McCloy Jan. 18, 1949 2,524,568 Kritzer Oct. 3,1950 2,526,032 La Porte Oct. 17, 1950 2,551,163 Rickert et al May 1,1951

